A Micro-Machined Microphone Based on a Combination of Electret and Field-Effect Transistor

Capacitive-type transduction is now widely used in MEMS microphones. However, its sensitivity decreases with reducing size, due to decreasing air gap capacitance. In the present study, we proposed and developed the Electret Gate of Field Effect Transistor (ElGoFET) transduction based on an electret and FET (field-effect-transistor) as a novel mechanism of MEMS microphone transduction. The ElGoFET transduction has the advantage that the sensitivity is dependent on the ratio of capacitance components in the transduction structure. Hence, ElGoFET transduction has high sensitivity even with a smaller air gap capacitance, due to a miniaturization of the transducer. A FET with a floating-gate electrode embedded on a membrane was designed and fabricated and an electret was fabricated by ion implantation with Ga+ ions. During the assembly process between the FET and the electret, the operating point of the FET was characterized using the static response of the FET induced by the electric field due to the trapped positive charge at the electret. Additionally, we evaluated the microphone performance of the ElGoFET by measuring the acoustic response in air using a semi-anechoic room. The results confirmed that the proposed transduction mechanism has potential for microphone applications.open1132Ysciescopu

Reliability Evaluation considering Structures of a Large Scale Wind Farm

Wind energy is one of the most widely used renewable energy resources. Wind power has been connected to the grid as large scale wind farm which is made up of dozens of wind turbines, and the scale of wind farm is more increased recently. Due to intermittent and variable wind source, reliability evaluation on wind farm is necessarily required. Also, because large scale offshore wind farm has a long repair time and a high repair cost as well as a high investment cost, it is essential to take into account the economic aspect. One of methods to efficiently build and to operate wind farm is to construct wind farm which is able to enhance a capability of delivering a power instead of controlling an uncontrollable output of wind power. Therefore, this paper introduces a method to evaluate the reliability depending upon structures of wind farm and to reflect the result to the planning stage of wind farm

Molecular detection of Edwardsiella tarda with gyrB gene isolated from pirarucu, Arapaima gigas which is exhibited in an indoor private commercial aquarium

The pirarucu, Arapaima gigas, which was displayed in commercial aquarium was found dead and was submitted for diagnostic examination. Bacteria from different organs of the fish were characterized using Vitek System®2 and showed 98% probability to Edwardsiella tarda. Polymerase chain reaction(PCR) result showed positive for E. tarda gyrB gene. The 16S rRNA gene was identical and exhibited 99% sequence similarity with the other known isolates of E. tarda available in the GenBank. This paper reports the isolation and detection of E. tarda with the gyrB gene in pirarucu, A. gigas, which was exhibited in an indoor private commercial aquarium in Seoul, South Korea.Key words: Arapaima gigas, commercial aquarium, Edwardsiella tarda, gyrB gene, pirarucu

A screen-printed carbon electrode modified with a chitosan-based film for in situ heavy metal ions measurement

SEM images and FTIR data of the working electrode surface showed that Mn+ ions were adsorbed on chitosan (Chit) and crosslinked chitosan-carbon nanotube (Chit-CNT) films. XPS revealed that chelation of Mn+ ions with the –NH2/–OH groups from chitosan, –COOH group from carbon nanotubes, and aqua ligands represents a possible structure of the active Mn+ species in the Chit-based film. The electrochemical behaviors of the Chit-based film modified screen-printed carbon electrode (SPCE) were characterized for individual and simultaneous detection of Cu2+, Pb2+, Hg2+, Zn2+, Cd2+, and As3+ ions. For individual detection, the concentration range was 0.50–3.00 ppm with a detection limit of 0.4 ppm for Cu2+; 1.0–4.0 ppm with a detection limit of 0.5 ppm for Pb2+; 1.0–5.0 ppm with a detection limit of 0.8 ppm for Hg2+. For simultaneous detection, the lab chip sensor was successfully used to determine the concentrations of Pb2+, Cu2+, Hg2+, and As3+ ions simultaneously

Effect of storage media and time on fin explants culture in the goldfish, Carassius auratus

The effect of storage media and time was investigated on fin explants culture in the goldfish (Carassius auratus). Fin explants under sterile conditions were able to produce cells at different storage media and time. On the outgrowth of cells, fin explants stored for seven days before culturing showed significantly higher growth (P<0.05) as observed on the fin explants stored in Dulbecco’s modified Eagles medium (DMEM, 84.44%), phosphate buffered saline (PBS, 62.42%) and in control/fresh fin explants (100%), compared with the explants with no storage medium (25.56%) at day three of culture. From day seven to 14, all caudal fin explants exhibited a 100% outgrowth of cells regardless of treatment. However, caudal fin explants kept for 10 days in 4°C showed a significant difference (P<0.05) from fin explants stored in DMEM (96.67%), PBS (75.57%) and the control (100%), as compared with no storage medium (no growth) on day three. Moreover, only 6.67% of no storage medium group could maintain outgrowth of cells, while other treatment group reached 100% of outgrowth after 14 days of culture.Key words: Carassius auratus, fin explants, goldfish, storage

Mid-term results in patients having tricuspidization of the quadricuspid aortic valve

BACKGROUND: Quadricuspid aortic valve (QAV) is a rare congenital anomaly. We investigate the mid-term results of aortic valve reconstruction by tricuspidization in patients with QAV. METHODS: We analyzed the outcome of eight consecutive patients who underwent aortic valve reconstruction surgery (AVRS) with pericardial leaflets with symptomatic quadricuspid aortic valve (QAV) disease between December 2007 and May 2012. AVRS consists of leaflet reconstruction and fixation of the sino-tubular junction in order to maintain coaptation of the new valve. RESULTS: Six males and two females were included; ages ranged from 19 to 63 years (mean age, 51 years). According to Hurwitz and Roberts’s classification, three patients had type A, three patients had type B, one patient had type C, and one patient had type E. All patients had significant aortic regurgitation (AR): moderate in three patients, moderate to severe in one patient, and severe in four patients. Concomitant ascending aorta wrapping with an artificial vascular graft was performed in one case. There was no occurrence of mortality during the follow-up period (42.4 ± 18.0 months). No redo-operation was required. The NYHA functional class showed improvement from 2.1 ± 0.2 to 1.1 ± 0.2 (p = 0.008). The latest echocardiograms showed AR absent or trivial in seven patients, and mild in one patient. The aortic valve orifice area index (AVAI) was 1.03 ± 0.49 cm(2)/m(2). Compared with preoperative echocardiograms, the left ventricular (LV) ejection fraction showed improvement from 57.6 ± 17.0 to 63.7 ± 13.2% (p = 0.036); the end-diastolic and end-systolic LV dimensions showed a significant decrease, from 63.5 ± 9.6 to 49.5 ± 3.1 mm (p = 0.012) and 43.6 ± 11.8 to 32.1 ± 5.4 mm (p = 0.012), respectively. CONCLUSION: In patients with QAV, AVRS with tricuspidization showed satisfactory early and mid-term results. Long-term follow-up will be necessary in order to study the durability of AVRS; however, it can be considered as a potential standard procedure

Convergence Theorems of Fixed Points for a Finite Family of Nonexpansive Mappings in Banach Spaces

We modify the normal Mann iterative process to have strong convergence for a finite family nonexpansive mappings in the framework of Banach spaces without any commutative assumption. Our results improve the results announced by many others

Approximate Proximal Point Algorithms for Finding Zeroes of Maximal Monotone Operators in Hilbert Spaces

Let H be a real Hilbert space, Ω a nonempty closed convex subset of H, and T:Ω→2H a maximal monotone operator with T−10 ≠ ∅. Let PΩ be the metric projection of H onto Ω. Suppose that, for any given xn∈H, βn>0, and en∈H, there exists x̄n∈Ω satisfying the following set-valued mapping equation: xn+en∈x¯n+βnT(x¯n) for all n≥0, where {βn}⊂(0,+∞) with βn→+∞ as n→∞ and {en} is regarded as an error sequence such that ∑n=0∞‖en‖2<+∞. Let {αn}⊂(0,1] be a real sequence such that αn→0 as n→∞ and ∑n=0∞αn=∞. For any fixed u∈Ω, define a sequence {xn} iteratively as xn+1=αnu+(1−αn)PΩ(x¯n−en) for all n≥0. Then {xn} converges strongly to a point z∈T−10 as n→∞, where z=limt→∞Jtu